1) Field of the Invention
The present invention relates to a method and system for controlling data transfer between, for example, a plurality of portable type mediums such as IC (Integrated Circuit) cards capable of storing digital money and a processing unit capable of gaining access to these portable type mediums.
2) Description of the Related Art
In the recent years, a variety of transaction apparatus capable of handling digital money (electronic money, E-money) and credit transactions have been developed, such as ATMs (Automatic Teller Machines), ECRs (Electric Cash Registers), digital money load terminals, electronic purses, and POS terminals/hand-held POS terminals (handy POSs)/POS servers constituting POS (Point Of Sales) systems.
The above-mentioned various transaction apparatus (processing units) gain access to IC cards (portable type mediums) storing digital money for accomplishing transaction based upon digital money, and usually accept mounting of a plurality of IC cards for access thereto. Conventionally, such transaction apparatus are equipped with IC card control circuits (card ports) whose number is identical to the number of IC cards to be mounted.
For instance, FIG. 28 shows the essence of a general transaction apparatus (processing unit) 300 in which four IC cards (portable type mediums) 320 to 323 are mountable. As shown in FIG. 28, the transaction apparatus 300 has four IC card control circuits 310 to 313 corresponding to the four IC cards 320 to 323.
These IC card control circuits 310 to 313 include card ports CP0 to CP3 to be connected to the IC cards 320 to 323, respectively, and control the IC cards 320 to 323 while conducting power supply/clock supply through the card ports CP0 to CP3 to the IC cards 320 to 323, thereby gaining direct access to these IC cards 320 to 323.
The connections between the IC card control circuits 310 to 313 and the IC cards 320 to 323 are made through data lines (Data), C4 signal lines (C4), C8 signal lines (C8), reset signal lines (Reset), power supply lines (Power Supply), clock supply lines (CLK Supply) and IC card mounting notice lines.
Although the IC card mounting notice lines are not shown in FIG. 28, the IC card mounting notice lines are 1-bit signal lines for informing each of the IC card control circuits 310 to 313 of whether each of the IC cards 320 to 323 is coupled with each of the card ports CP0 to CP3. Each of the IC card control circuits 310 to 313, which has received a notice on the mounting of each of the IC cards 320 to 323 through each of the IC card mounting notice lines, starts the power supply/clock supply to each of the IC cards 320 to 323.
In addition, the power supply lines (Power Supply) and the clock supply lines (CLK Supply) always supply power and a clock signal to the IC cards 320 to 323 connected thereto. On the other hand, in the case of the data lines (Data), the C4 signal lines (C4), the C8 signal lines (C8) and the reset signal lines (Reset), the lines connected to the IC cards 320 to 323 to which the IC card control circuits 310 to 313 have access are made to be placed into activation.
In the case of the example of FIG. 28, in a state where the four IC cards 320 to 323 are connected to the transaction apparatus 300, the two IC card control circuits 310 and 312 operate simultaneously in response to instructions from a CPU (not shown) in the transaction apparatus 300 so that the IC card control circuit 310 gains access to the IC card 320 while the IC card control circuit 312 makes access to the IC card 322. Upon receipt of commands from the IC card control circuits 310, 312, the IC cards 320, 322 return responses to these commands to the IC card control circuits 310, 312, respectively.
By simultaneously making access to the two IC cards 320, 322 in this way, the transaction apparatus 300 can conduct transaction processing, such as transfer of digital money between the two IC cards 320, 322, as indicated by arrows A1, A2 in FIG. 28.
Since the above-described conventional technique needs the installation of card ports (IC card control circuits), whose number is identical to the number of a plurality of IC cards, for controlling the plurality of IC cards, if a need exists for increasing the number of IC cards to be controlled by the transaction apparatus, then this results in an increase in the number of card ports to be provided in the transaction apparatus.
As mentioned above, there is a need to place at least 7 lines including the data line, the C4 signal line, the C8 signal line, the reset signal line, the clock supply line, the power supply line and the IC card mounting notice line in connection with one card port. Thus, for example, in the case of dealing with six IC cards with one processing unit, that processing unit requires not only 6 IC card control circuits but also at least 42 (=6*7) lines, leading to an increase in the manufacturing cost of the processing unit (transaction apparatus). Particularly, if the processing unit (transaction apparatus) is formed into an integrated circuit, the aforesaid large numbers of lines and IC card control circuits are required to be integrated at high density, which contributes to a rise of its manufacturing cost and an increase in its circuit scale.
Meanwhile, in most cases, the processing unit actually handling digital money gains access to only one IC card or makes access to two IC cards as shown in FIG. 28, but seldom needed to concurrently make access to three or more IC cards. For this reason, in the case that six card ports are provided to cover six IC cards, of these card ports, four or more card ports frequently run to waste.
The present invention has been developed in consideration of this situation, and it is therefore an object of this invention to provide a data transfer control method and a data transfer control system which are capable of providing access (data transfer) to portable type mediums whose number is larger than the number of card ports on the processing unit side.
For this purpose, in accordance with this invention, there is provided a data transfer control method of controlling data transfer between a plurality of portable type mediums and a processing unit having an ability to gain access to the plurality of portable type mediums, wherein the processing unit is equipped with one or more ports for the plurality of portable type mediums, and the portable type mediums, whose number is larger than the number of the ports, are connected through a demultiplexer to the ports so that the demultiplexer selectively switches the ports and the portable type mediums to be accessed by the processing unit to establish connection between the portable type mediums and the ports.
Furthermore, in accordance with this invention, there is provided a data transfer control system, interposed between a plurality of portable type mediums and a processing unit capable of gaining access to the plurality of portable type mediums, for controlling data transfer between the plurality of portable type mediums and the processing unit, and comprising a demultiplexer capable of making connection between one or more ports for the portable type mediums in the processing unit and the plurality of portable type mediums whose number is larger than the number of the ports, with the demultiplexer selectively switching the ports and the portable type mediums of the plurality of portable type mediums to be accessed by the processing unit to establish connection between the ports and the portable type mediums.
With the data transfer control method and the data transfer control system, since the switching of the connection states between the ports and the portable type mediums by the demultiplexer allows the processing unit access to the portable type mediums whose number is larger than the number of the ports on the processing unit side, in the case of increasing the number of portable type mediums to be controlled by the processing unit, there is no need to increase the numbers of ports and the number of portable medium control circuits on the processing unit side.
Accordingly, it is possible to increase the number of portable type mediums to be controlled without raising the processing unit manufacturing cost. Particularly, in the case that the processing unit is constructed as an integrated circuit, even if the number of portable type mediums to be controlled increases, it is possible to eliminate the need to integrate a large number of lines and portable type medium control circuits at high density, which contributes considerably to the reduction of manufacturing cost and circuit scale.